1. Field of the Invention
The present invention relates to a toothbrush with tapered acicular bristles, and more particularly, to a toothbrush with tapered acicular bristles having soft and hard bristles together.
2. Background of the Related Art
In general, a toothbrush having bristles tapered at pointed ends to increase removal efficiency of the tartar and the plaque from the teeth and to prevent an injury to the gums during brushing teeth has been invented, and since then, such a toothbrush has become more popular due to demonstration of its effectiveness.
Prior art relating to a toothbrush as described above is known. See for example; Korean Patent Nos. 130932, 261658 and 311360, and Korean Utility Model Registration Nos. 114700 and 244827 invented by the present inventor.
Korean Patent No. 130932 discloses a method of making the diameter of the end portions of PBT bristles into about 0.1–0.03 mm by tapering the PBT toothbrush bristles having a diameter of 0.15–0.2 mm to a length of 4–8 mm from the pointed ends of the bristles after decomposing them with chemicals. The toothbrush having the bristles manufactured by the above method has several advantages in that it is less likely to injure the gums, can remove pollutants and bacteria stained on the user's teeth because the bristles can be inserted into the periodontal pockets of the gums, and can easily remove foreign matters because it can be easily inserted between teeth. However, some consumers are unsatisfied with the toothbrush as they do not experience good brushing feeling due to the excessively soft bristles.
Korean Utility Model Registration No. 114700 discloses a toothbrush having different tapered lengths by tapering the end quarter of a bristle (the tapered length is about 8 mm in case of the bristle length of 32 mm) at one side of the brush and by tapering the end ⅛th (the tapered length is about 4 mm in case of the bristle length of 32 mm) at the other side. The toothbrush manufactured by the above method has more overall hardness than that of Korean Patent No. 130932 yet achieves the same tartar and plaque removal effectiveness as that of the Korean patent.
Korean Patent No. 261658 discloses a method for tapering the diameter of the end portions of the PBT bristles from 0.04–0.08 mm using the same method as that of Korean patent No. 130932, wherein physical and chemical methods are combined to save manufacturing costs. People accustomed to nylon bristles, which are rigid, have a preference for the toothbrush manufactured by the above patent, but it has a disadvantage that it is less effective for removing foreign matters inside the periodontal pockets as its diameter is relatively large.
Korean Utility Model Registration No. 244827 discloses a toothbrush including tapered bristles which are formed of 0.02–0.03 mm in diameter at the ends to be easily inserted into periodontal pockets and are formed to be about 3.5 mm or less in length to provide hardness to the bristles. The toothbrush manufactured by the above method provides consumers with a relatively satisfactory result in hardness, tartar removing effect and insertion of the tapered bristle ends into the periodontal pockets.
Korean Patent No. 311360 discloses a toothbrush having on both sides tapered bristles of a general height to be more easily inserted between teeth and into periodontal pockets. The toothbrush has at least one protrusion 1–10 mm in height to serve as an interdental toothbrush.
Such toothbrushes of the prior arts have been all manufactured and sold as separate products, but toothbrushes having all the above advantages of the prior arts have not yet been disclosed.